I'd add that most technical companies today, unless at the scale of Google/Facebook do not necessarily (and most likely don't) have very sophisticated tooling in place. You can imagine Jenkins is always in place and codes are splitted into "self-contained" repos; I don't know if Google/Facebook uses Jenkins, but I know Netflix certainly does.

I haven't heard much about Microsoft or Amazon, though I do know from a friend working at Apple their toolings are not always consistent from team to team. I would appreciate if we have someone from these other big tech companies to discuss their development workflow.

As a SRE/DevOps, I love working on internal toolings because I get to feel like creating my own programming language - I can be creative but focus on solving problems in my domains.